title: Soil water stress affects both cuticular wax content and cuticle-related gene expression in young saplings of maritime pine (Pinus pinaster Ait).
abstract: BACKGROUND
  The cuticle is a hydrophobic barrier located at the aerial surface of all terrestrial plants. Recent studies performed on model plants, such as Arabidopsis thaliana, have suggested that the cuticle may be involved in drought stress adaptation, preventing non-stomatal water loss. Although forest trees will face more intense drought stresses (in duration and intensity) with global warming, very few studies on the role of the cuticle in drought stress adaptation in these long-lived organisms have been so far reported.
  
  
  RESULTS
  This aspect was investigated in a conifer, maritime pine (Pinus pinaster Ait.), in a factorial design with two genetic units (two half-sib families with different growth rates) and two treatments (irrigated vs non-irrigated), in field conditions. Saplings were grown in an open-sided greenhouse and half were irrigated three times per week for two growing seasons. Needles were sampled three times per year for cuticular wax (composition and content) and transcriptome (of 11 genes involved in cuticle biosynthesis) analysis. Non-irrigated saplings (i) had a higher cuticular wax content than irrigated saplings and (ii) overexpressed most of the genes studied. Both these trends were more marked in the faster growing family.
  
  
  CONCLUSIONS
  The higher cuticular wax content observed in the non-irrigated treatment associated with strong modifications in products from the decarbonylation pathway suggest that cuticular wax may be involved in drought stress adaptation in maritime pine. This study provides also a set of promising candidate genes for future forward genetic studies in conifers.
authors.affiliation: INRA, UMR 1202, BIOGECO, F-33610, Cestas, France. leprovost@pierroton.inra.fr
authors.forename: Grégoire
authors.initials: G
authors.lastname: Le Provost
authors.forename: Frédéric
authors.initials: F
authors.lastname: Domergue
authors.forename: Céline
authors.initials: C
authors.lastname: Lalanne
authors.forename: Patricio
authors.initials: P
authors.lastname: Ramos Campos
authors.forename: Antoine
authors.initials: A
authors.lastname: Grosbois
authors.forename: Didier
authors.initials: D
authors.lastname: Bert
authors.forename: Céline
authors.initials: C
authors.lastname: Meredieu
authors.forename: Frédéric
authors.initials: F
authors.lastname: Danjon
authors.forename: Christophe
authors.initials: C
authors.lastname: Plomion
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Gion
mesh_terms: D055864:Droughts; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D028223:Pinus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D012987:Soil / Q000032:analysis; D014867:Water / Q000032:analysis / Q000378:metabolism*; D014885:Waxes / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D012987:Soil; D014885:Waxes; D014867:Water